VMS Help REPLY, Qualifiers, /INITIALIZE_TAPE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /INITIALIZE_TAPE=identification-number

    Sends a message to the magnetic tape file system indicated by
    the identification number to initialize a magnetic tape volume.
    This qualifier can be used whenever the file system requests the
    mounting of a new volume. The system performs normal protection
    and expiration checks before initializing the volume. The current
    terminal must be enabled as an operator terminal for TAPES.

    If the tape drive cannot read the volume, the mount fails and
    an error message is returned. Use the /BLANK_TAPE qualifier to
    override the checking of information on a volume label.